i remember reading this tip on the steam community or reddit or wherever, unfortunately didn't work for me. i started Steam Big Picture Mode, unplugged mouse and keyboard, started the game with only the controller connected and it still didn't recognize it, no idea what went wrong. thinking about it now it maybe interpreted my DAC as an input device or whatever.

in the end i didn't care that much, as i only installed DS2 because my SO was playing it. apparently she didn't like the game anyways, so i just uninstalled it and that was it :D